30 lines
1.2 KiB
MiniZinc
30 lines
1.2 KiB
MiniZinc
%--------------------------------------------------------------------%
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% Requires that a set of tasks given by start times 's',
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% durations 'd', and resource requirements 'r',
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% never require more than a global
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% resource bound 'b' at any one time.
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% Assumptions:
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% - forall i, d[i] >= 0 and r[i] >= 0
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%--------------------------------------------------------------------%
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predicate cumulative(array[int] of var int: s,
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array[int] of var int: d,
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array[int] of var int: r, var int: b) =
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assert(index_set(s) == index_set(d) /\
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index_set(s) == index_set(r),
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"cumulative: the array arguments must have identical index sets",
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assert(lb_array(d) >= 0 /\ lb_array(r) >= 0,
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"cumulative: durations and resource usages must be non-negative",
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let {
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set of int: times =
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lb_array(s) ..
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max([ ub(s[i]) + ub(d[i]) | i in index_set(s) ])
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}
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in
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forall( t in times ) (
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b >= sum( i in index_set(s) ) (
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bool2int( s[i] <= t /\ t < s[i] + d[i] ) * r[i]
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)
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)
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)
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);
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